Re: [PATCH] arch/arm/kernel: use cpu_relax() in halt loops

[Jonathan NeuschÃfer]

On Tue, Dec 14, 2010 at 10:51:26PM +0000, Russell King - ARM Linux wrote:
> On Tue, Dec 14, 2010 at 11:48:48PM +0100, Jonathan NeuschÃfer wrote:
> > Looking throught arch/arm/kernel/ I found some halt loops.
> > I just thought we could save some power here using cpu_relax(),
> > or am I missing something?
> 
> #if __LINUX_ARM_ARCH__ == 6
> #define cpu_relax()                     smp_mb()
> #else
> #define cpu_relax()                     barrier()
> #endif
> 
> IOW, it's either a memory barrier or compiler barrier on ARM; it
> doesn't do any power saving.

Okay, thanks for that explanation.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/